so i took a script form a forum post,http://forum.unity3d.com/viewtopic.php?t=46222 , and changed to be used for me:

    //
var inventory : Array;
static private var InventoryOpen: boolean = false;
var InventoryGUI:Texture2D;
var SpawnPoint: Transform;
var ChatOpnener;

var doWindow : boolean = false;

//  
public var emptyTex : Texture;

//  (- )
public var inventorySizeX = 4;
public var inventorySizeY = 5;

//     
var iconWidthHeight = 40;

//   ( X  Y)
var spacing = 4;

// 
public var offSet = Vector2( 100, 100 );


//      (. Update())
private var itemImage : Texture2D;


//   
class InventoryItem
{
   //    
   var worldObject : GameObject;
   //,       
   var texRepresentation : Texture2D;
}

//  
function Awake()
{
ChatOpnener = GameObject.Find("Tank Weapon Shop Keep").GetComponent("ActiveChat");
offSet = Vector2(Screen.width/2+offSet.x,Screen.height/2+offSet.y);
   inventory = new Array(inventorySizeX);

    for( var i = 0; i < inventory.length; i ++ )
    {
        inventory[i] = new Array(inventorySizeY);
    }
}


function OnGUI() {

   var texToUse : Texture2D;
   var currentInventoryItem : InventoryItem;
if(InventoryOpen&&!ChatOpnener.ChatIsOpen){
GUI.Label(Rect(Screen.width/2-200,Screen.height/2-200,400,400),InventoryGUI);
    //   
    for( var i = 0; i < inventory.length; i ++ )
    {
        //   
        for( var k = 0; k < inventory[i].length; k ++ )
        {
           texToUse = emptyTex;
           currentInventoryItem = inventory[i][k];

            //    I-   K- , 
            if( inventory[i][k] != null )
            {
                texToUse = currentInventoryItem.texRepresentation;
            }

            var it = GUI.Button( new Rect( offSet.x+k*(iconWidthHeight+spacing), offSet.y+i*(iconWidthHeight+spacing), iconWidthHeight, iconWidthHeight ), texToUse );
            GUI.Button( new Rect( offSet.x+k*(iconWidthHeight+spacing), offSet.y+i*(iconWidthHeight+spacing), iconWidthHeight, iconWidthHeight ), texToUse );
            var w : int = 0;
            var h : int = 0;
            if (it && currentInventoryItem != null) 
            { 
            print("TEST");
                Instantiate(currentInventoryItem.worldObject,SpawnPoint.transform.position,Quaternion.identity);
                currentInventoryItem.texRepresentation = null; 
                inventory[i][k] = null;


            }

                //  
            Debug.Log("item droped");
            }
        }
    }
}



function AddItem( item : InventoryItem )
{
    //   
    for( var i = 0; i < inventory.length; i ++ )
    {
        //   
        for( var k = 0; k < inventory[i].length; k ++ )
        {
           //  ,       
           if( inventory[i][k] == null )
            {
                inventory[i][k] = item;
                return;
            }
        }
    }   

    //  ,  -   
}

function AddItem1( worldObject : GameObject, texRep : Texture2D )
{
   var newItem = new InventoryItem();

    newItem.worldObject = worldObject;
    newItem.texRepresentation = texRep;

   AddItem( newItem );   
}

function Update(){
if(Input.GetKeyDown(KeyCode.I)){
if(InventoryOpen){
InventoryOpen=false;
}else{
InventoryOpen=true;
}
}
}

but when i added this part:

if (it && currentInventoryItem != null) 
                { 
                print("TEST");
                    Instantiate(currentInventoryItem.worldObject,SpawnPoint.transform.position,Quaternion.identity);
                    currentInventoryItem.texRepresentation = null; 
                    inventory[i][k] = null;


                }

it lagged my game REALLY bad, it must e something here, just try and help me please, if more info is needed tell me